Adjustable tail pipe for well tools



June 3, 1969 L. B. SCOTT ADJUSTABLE TAIL PIPE FOR WELL TOOLS Filed March24, 1967 za w wwf/W0@ 1 /444//1/ 144W! Sheet June 3, 1969 L, B, SCOTT3,447,606

ADJUSTABLE TAIL PIPE FOR WELL' TOOLS Filed March 24, 1967 sheet i of s5/ I 1 /i y; s l i 'f 7 iL 7 I fd I N -fz l /Z Il i J/\ 9 u? .iune 3,w69 l.. B. SCOTT ADJUSTABLE TAIL PIPE FOR WELL TOOLS Sheet Filed March24, 1967 55 55g@ 4/// Z c v A? i United States Patent O U.S. Cl. 166-2378 Claims ABSTRACT OF THE DISCLOSURE An adjustable tail pipe for welltools telescopically adjustable from a iirst position, at which itprojects from a tool body to a second position at which it projectsfurther from the tool and is locked in the second position bymechanically engaged lock elements.

The present invention relates to a tail pipe lock for well tools, andmore particularly to a telescopic tail pipe assembly which is adapted tobe landed at the bottom of a well such as an oil or gas well, or thelike drilled hole, or landed on some other abutment placed in the well,and when landed to cause operation of a well tool thereabove in arunning in string of pipe, such as drill pipe or other tubing or wellpipe.

This invention is an improvement in the adjustable tail pipe for welltools disclosed in the pending application for United States Patent,Serial No. 618,910 led in the name of Theodore A. Raugust on Feb. 27,1967.

In the making of drill stem tests of wells during the drillingoperation, a testing apparatus is run into the well on drill pipe, suchtesting apparatus including means for taking a sample of the uids in theearth formation about the well bore and between a pair of axially spacedpackers which are adapted to be set in the open well bore or open holeso as to straddle the earth formation from which it is desired that thesample be taken, and the packers being Separated by a perforated orslotted pipe section into which the formation fluid is to pass. In someinstances the effective bottom of the well is not in a location relativeto the zone or formation to be tested as to enable proper setting of thestraddle packers by setting a tail pipe down on the bottom of the well.Heretofore, if an improper seal was made by the packers, for example dueto the fact that the packers are too low relative to the zone to bestraddled, it has been necessary to pull the entire length of drill pipeto change the effective distance between the bottom of tail pipe and thestraddle packer. Such an operation is costly and time consuming.

The adjustable tail pipe of the aforementioned pending applicationprovides hydraulic lock means in an extensible tail pipe adapted tooperate a well tool, and which is adjustable in length between first andsecond lengths.

More specifically, an object of the invention is to provide anadjustable tail pipe construction in which an adjustment of theeffective length of the tail pipe is made by simple manipulation of thepipe string in which the well tool and tail pipe are installed and inwhich a positive lock is provided to hold the tail pipe in its extendedcondition.

In accomplishing the foregoing, it is another object of the invention toprovide an adjustable tail pipe construction and lock means for holdingthe same in a position of adjusted length without regard to the depth ofthe well bore and the hydrostatic pressure of fluid in the Well bore.

Another object is to provide the combination of a well tool adapted tobe operated in response to the setting down of the Weight of the runningin string of pipe, and an adjustable tail pipe and positive lock meansalso operated Lce in response to the setting down of the weight of therunning in string of pipe to cause operation of the well tool at anadjusted elevation in the well bore. More specifically, such combinationincludes a straddle packer of a drill stem tester.

Other objects and advantages of the invention will be hereinafterdescribed or will become apparent to those skilled in the art and thenovel features of the invention will be defined in the appended claims.

In one of its aspects, the invention briey is embodied in an adjustabletail pipe for operating a well tool upon engagement of the tail pipewith the bottom of a well, including telescopic upper and lowersections, releasable means interconnecting the sections together in afirst relative position and releasable responsive to the application ofa force tending to telescopically shift the sections from the firstposition to a contracted position, and means including coengageable lockelements on one of the sections for positively interconnecting thetelescopic sections in a second relative position following telescopicshifting of the sections to an extended position, wherein thelast-mentioned means include opposing shoulders axially spaced on thetelescopic sections, and the lock elements include expansible wedgemembers and means for expanding the expansible wedge members, theexpansible wedge members being engageable with one of the opposingshoulders and the means for expanding the same being engageable with theother of the opposing shoulders, and means for effecting fluid pressureresponsive expansion of the wedge members into engagement With the otherof the opposing shoulders.

In another of its aspects the invention briefly includes an adjustabletail pipe for operating a well tool upon engagement of the tail pipewith the bottom of a well, the tail pipe including an upper tubular bodyadapted for connection beneath a well tool, a lower tubular bodyincluding a rod telescopically extending into the upper body, means forreleasably interconnecting the bodies in relative positions with the rodextended fully into the upper body, an upwardly facing shoulder adjacentthe upper end of the rod, a downwardly facing shoulder in and adjacentthe lower end of the upper body, lock means on the rod above theupwardly facing shoulder, means for limiting telescopic extension of therod from the upper body to a relative position of the upper body andlower body at which the downwardly facing shoulder is above the lockmeans following release of the interconnecting means, and means forexpanding the lock means for engagement with the `downwardly facingshoulder and engagement with the upwardly facing shoulder to main; tainthe rod in the extended position.

In the drawings:

FIG. l is a view generally showing in elevation a drill stem testingtool including a straddle packer set in a well bore in a first,ineffective position, with the adjustable tail pipe of the inventionlanded at the bottom of the well;

FIG. 2 is a View generally corresponding to FIG. 1, but showing thetester tool and straddle packer set in a second, effective position inthe well bore, with the tail pipe adjusted, locked in a position ofextended length, and landed at the bottom of the well;

FIG. 3a is an enlarged view in vertical section showing the upperportion of the adjustable tail pipe and lock in condition for runninginto the well bore;

FIG. 3b is a downward extension of FIG. 3a;

FIG. 4 is a transverse sectional view as taken on the line 4-4 of FIG.3a;

FIG. 5a is a fragmentary view in side elevation of the portion of FIG.3b embraced by the line Sa-Sa, showing the frangible retaining ring forreleasably holding the tail pipe in the position of FIG. 1;

FIG. b is a view corresponding to FIG. 5a, but showing the retainingring sheared in response to downward force applied by the running instring;

FIG. 6 is a view in longitudinal section showing the tail pipe assembly,with central portions broken out, lling with iiuid as the tail pipe isbeing stretched out and the running in string is elevated after shearingof the retaining ring as seen in FIG. 5b;

FIG. 7a is a fragmentary View in longitudinal section showing the tailpipe lock stretched out and under tension responsive to upward movementof the running in string;

FIG. 7b is a view corresponding to FIG. 7a, but showing the lockelements pressure loaded to the locking position during downwardmovement of the upper tail pipe section relative to the lower tail pipesection; and

FIG. 7c is a view corresponding to FIGS. 7a and 7b, but showing theupper tail pipe section locked against further downward movementrelative to the lower tail pipe section.

Like reference characters in the several views of the drawings and inthe following description designate corresponding parts.

Referring to FIG. 1, there is illustrated a well tool assembly embodyingthe present invention, such assembly including a hydraulic main valve ofconventional construction and forming part of a drill stern testeradapted to be mounted in a running in string of pipe, the tester alsoincluding a straddle packer assembly consisting of an upper packer and alower packer adapted to engage the well bore Wall and form spaced sealsisolating an intermediate length of perforated pipe into which a sampleof formation uid is to be taken. The packers are typically set, orcaused to be deformed and moved outwardly into sealing engagement withthe well Wall in response to the setting down of weight on a tail pipewhich depends from the straddle packer assembly, all is as well known inthe art.

However, as shown in FIG. 1 the potentially productive earth formationto be tested may consist of narrow sand strata, one of which isdesignated F. Thus, if the packers do not properly isolate the formationF and one of the packers is disposed in the sandy formation F, anineffective seal and an ineffective test may result. It is not uncommonin certain oil and gas producing areas that the upper packer may bedisposed in an improper location as illustrated in FIG. l and the pipestring must be pulled from the well to change the length of the tailpipe so that upon re-running the string of pipe and the new tail pipe,the packers will be properly set as shown in FIG. 2. Such round trippingof the running in string to modify the tool is time consuming andcostly. Many such problems may be avoided by adjustment of the effectivelength of the tail pipe, and in FIG. 2 the adjustable tail pipe has beenextended to raise the location of the packers in the Well bore so thatthey properly isolate the formation F and are engaged with the well wallat locations where better sealing is possible.

The adjustable tail pipe comprises an upper tubular section 1 and alower tubular section 2 telescopically coengaged and interconnected at 3by frangible means which will be more fully described and whichmaintains the first effective tail pipe length as shown in FIG. 1 untilbroken to allow the tail pipe to telescope to the second effectivelength shown in FIG. 2.

Referring to FIGS. 3a through 5b, the structure of the adjustable tailpipe will be described in detail. As seen in FIG. 3a, the tubular body 1is connected as at 4 to a head 5 which is adapted to be connected as bya pin and box threaded joint 6 to the lower end of the straddle packerassembly. The head 5 has a wall 7 closing the upper end of body 1 andseparating the interior of body 1 from the interior of the packerassembly. At its lower end the upper body 1 has a pair of downwardlyextended connector fingers 8, 8 forming a part of the frangibleconnection 3, whereby the lower body 2 is connected to the upper body 1,as seen in FIGS. 3b and 5a.

The upper end of body 2 is axially slotted at 9, 9 to receive fingers 8,8 and in addition is circumferentially slotted at 10 to receive arcuateretaining ring segments 11 and 12, these segments 11 and 12 also extendarcuately through slots 13 in fingers 8, 8 so as to interlock thefingers with the body section 2. Ring segments 11 and 12 are held inslots 10 and 13 by a wire or band 14, and thus the body sections 1 and 2are held in a first axial relationship. Clearance space 15 is providedbetween the upper end of body 2 and the lower end of body 1, as well asbetween the bottom of fingers 8, 8 and the bottom of slots 9. The ringsegments are composed of such material, aluminum for example, as will beshearable by the side walls of lingers 8, 8 and slots 9 when suicientdownward force is applied to the upper body 1 and the lower body 2 islanded on the bottom of the well. FIG. 5 b illusstrates the sheared ringsegment 12, and thereafter, the body sections 1 and 2 are movable to asecond axial relationship, as Iwill hereinafter be described.

Referring again to FIGS. 3a and 3b, the tail pipe assembly includes aninner tubular member or connecting rod 16 formed as part of or connectedto the body 2 as at 17 and extended upwardly within the body 1 so as tobe telescopically adjusted relative to the body 1 upon release of theretaining means 3. At the upper end of connecting rod 16 is lock meansgenerally indicated at 18.

This lock means includes a support 19 in the form of a tubular extensionof the connecting rod 16 formed on or connected to the latter as at 20.On the support 19 is a lower shoulder or upwardly facing abutment 21 andat the upper end of the support 19 is a nut providing a downwardlyfacing abutment 22. Lock means 18, therefore, is mounted on the support19 between the upwardly and downwardly facing abutments 21 and 22.

More specifically, the lock means 18 comprises an annular divider piston23 which sealingly engages the inside wall of body 1 and the support 19,the piston separating the space between support 19 and body 1 into anupper chamber 24 and a lower annular chamber 25 deiined betweenconnecting rod 16 and the -body 1.

Passage means are provided for balancing the pressure in the chambers 24and 25. Such passage means includes a passage 26 extending through theconnecting rod 16 and including a passage 26a in the support 19. At itslower end, passage 26 leads to a passage 26b in a bull nose 27, at thelower end of the body 1, the passage 26b typically communicating withthe well bore. In passage 26 is a check valve including a seat 28circumscribing the passage and engageable by a downwardly seating -ballvalve 29. Thus when pressure inside chamber 24 is less than pressure offluid in the well the valve will open to fill the chamber 24 with iiuidat the same pressure as well pressure.

In addition, body 1 s formed with a passage 30 (see FIG. 3b) included inthe pressure -balancing passage means which leads between the chamber 25and the well bore outside the body 1. Communication between chambers 24and 25 is established through a number of restricted passages 31 for apurpose which will hereinafter more fully appear, but it will now beapparent that pressure will be normally balanced across piston member23, but under some circumstances, as will be later described, balance isretarded by the restriction to flow through restricted passage 31.

The lock means 1'8 includes also laterally outwardly shiftable lockelements in the form of wedge members 32 arranged at angularly spacedlocations about piston 23. Each wedge member is provided with a T-head33 shiftably mounted in a T-slot 34 in the lower portion of piston 23.These wedge elements 32 are held retracted as shown in FIG. 3a by meansof a resilient band 35 which encircles the wedge elements. Beneath theWedgeelements 32 is an expander 36 slidably disposed on the support 19and engageable with abutment 21. The expander 36 has a conical endengageable with the lower ends of the lock elements so that upon axialmovement of the expander and elements toward one another the elementswill be expanded laterally outwardly, but upon opposite movement of theexpander and the elements the latter will move inwardly.

In the normal or running in condition shown in FIGS. 3a and 3b, it willbe noted that the expander 36 is seated against the shoulder 21 and thatthe lock elements 32 are retracted. Under these conditions the body 1and body 2 are maintained in their rst relative position of compositelength by the shearable retaining ring segments 11 and 12. Duringrunning of the string into the Awell bore, the tail pipe may fill withfluid through the check valve 29 and the passage 30 in the body 1.

Whenv the tail pipe reaches the bottom of the well, as shown in FIG. l,the weight of the running in string of pipe will shear the ring segments11 and 12 and thereafter the weight of the running in string will causeexpansion of the packers into engagement with the well wall. If it appears that the packers are not properly positioned to provide a goodseal with the formation then, as will now be described, the effectivelength of the tail pipe may be extended.

In FIG. 6 is illustrated the next manipulative step, whereby the tailpipe is extended in length, and is lled with fluid as its internalvolume expands. This step involves lifting up on the running in string,during which body 2 will remain at or adjacent the bottom of the holeand the upper body 1 will move upwardly telescoping with respect to therod 16 until such telescoping is arrested and the tail pipe assembly issupported in tension as shown in FIG. 7a. During telescopic extension ofthe tail pipe, an intermediate state of which is shown in FIG. 6, thecheck valve 29 will open to allow entry of liuid into the expandingspace within the tail pipe, and fluid may also enter port 30 in body 1.

Referring more specifically to FIG. 7a, it will be noted that when thetail pipe is supported in tension, the upper body 1 has telescopedupward relative to the lower body 2 causing an internal abutment meanson shoulder 40 of the body 1 to engage the lower end of expander 36,moving the latter upwardly off of shoulder 21. The lock elements 32 arecammed outwardly and the T-heads 33 engage at their upper ends with thepiston 23 which, in turn, abuts with the upper abutment means 22. Thusthe lower section of the tail pipe, including body 2 and rod 16, issuspended from the upper section of the tail pipe.

In the next phase of manipulation of the running in string, as shown inFIGURE 7b, the assembly is again lowered to cause the lower section ofthe tail pipe to land at the bottom of the Well, which will arrestfurther downward movement of the tail pipe assembly as a unit, but theupper section will continue to move downwardly, telescoping over the rod16, thereby reducing the internal volume of iluid within the assembly.The end wall 7, at the top of body 1, displaces uid from chamber 24 intochamber 25 through restricted passages 31 in the barrier piston 23,while check valve 29 closes to prevent flow from chamber 24 through thepassageways 26a in support 19 and 26 in connecting rod 16. lnasmuch asthe chamber 25 opens to the exterior of the tail pipe assembly throughthe port 30, the fluid displaced from chamber 24 into chamber 25provides a differential pressure across the barrier piston 23 actingdownwardly on the latter and forcing it downwardly, thereby causing alaterally outward force to be imposed on the lock elements 32 byexpander 36, which in turn is forced downwardly against the downwardlymoving abutment 40 of upper body 1. As such downward movement continues,the expander 36 will again engage the abutment 21 on stationary body 19arresting downward movement of expander 3-6 while the differentialpressure across barrier piston 23 continues to maintain the lockelements 32 in the expanded condition.

In the final stage of operation, as seen in FIG. 7c, it will be notedthat the upper ends of the expanded lock elements engage a downwardlyfacing abutment 41 within upper body -1 so that the weight of therunning in string will be transmitted from abutment 41 to the lockelements 32 and through them to expander 36 which is abuttingly engagedwith upwardly facing abutment 21. At this time, of course, the tail pipeassembly is adjusted to its second or extended condition having aneffective length in excess of its above-described rst position aI'distance substantially equal to the length of the connecting rod.Various rod lengths may be employed, say on the order of -ve feet, so asto enable setting of the packers at a ve foot higher elevation in "FIG,2 than in FIG. 1.

Inasmuch as the forces imposed on the tail pipe assembly and the lockingmeans -18 as they are being operated l are substantial, the restrictedpassageways 31 through the barrier piston 23 are preferably such as tocause a dashpotting of the downward movement of the upper body 1 throughthe stages shown in FIGS. 7b and 7c, so as to relieve the lock means ofheavy shock loads.

While the specific details of the invention have been herein shown anddescribed, changes and alterations may be made ywithout `departing fromthe spirit of the invention as dened in the appended claims.

I claim:

1. An adjustable tail pipe for operating a well tool upon engagement ofsaid tail pipe with the bottom of a well, comprising telescopic upperand lower sections, releasable means interconnecting said sectionstogether in a rst relative position and releasable responsive to theapplication of of a force tending to telescopically shift said sectionsfrom said first position to a contracted position, and means includingcoengageable lock elements on one of said sections for positivelyinterconnecting said telescopic sections in a second relative positionfollowing telescopic shifting of said sections to an extended position,wherein said `last-mentioned means include opposing shoulders axiallyspaced on said telescopic sections, and said lock elements includeexpansible wedge members and means for expanding said expansible wedgemembers, said expansible wedge members being engageable with one of saidopposing shoulders and said means for expanding the same beingengageable with the other of said opposing shoulders, and means foreffecting fluid pressure responsive expansion of said wedge members intoengagement with said other of said opposing shoulders.

2. An adjustable tail pipe for operating a well tool upon engagement ofsaid tail pipe with the bottom of a well, comprising telescopic upperand lower sections, releasable means interconnecting said sectionstogether in a first relative position and releasable responsive to theapplication of a force tending to telescopically shift said sectionsfrom said first position, and means including coengageable lock elementson said sections for positively interconnecting said telescopic sectionsin a second relative position following telescopic shifting of saidsections, one of said telescopic sections including a connecting rodtelescopically extending into the other section, said means forinterconnecting said sections in said second position including asupport at the inner end of said rod, laterally movable lock elements onsaid support, axially opposing shoulders on said support and said othersection, and means for laterally moving said lock elements from aretracted position to a laterally shifted position between saidshoulders to hold said sections in said second position, wherein themeans for laterally moving said lock elements includes an expander andmeans for effecting engagement of said lock elements with said expanderincluding a uid pressure operated piston, said lock elements beingcarried by said piston, said one of said sections having a chamber inwhich said piston is disposed, and said sections having passage meansfor admitting fluid to said chamber and discharging fluid from saidchamber.

'3. An adjustable tail pipe for operating a well tool upon engagement ofsaid tail pipe with the bottom of a well, comprising telescopic upperand lower sections, releasable means interconnecting said sectionstogether in a first relative position and releasable responsive to theapplication of a force tending rto telescopically shift said sectionsfrom said iirst position, and means including coengageable lock elementson said sections for positively interconnecting said telescopic sectionsin a second relative position following telescopic shifting of saidsections, one of said telescopic sections including a connecting rodtelescopically extending into the other section, said means forinterconnecting said sections in said second position including asupport at the inner end of said rod, laterally movable lock elements onsaid support, axially opposing shoulders on said support and said othersection, and means for laterally moving said lock elements from aretracted position to a laterally shifted position between saidshoulders to hold said sections in said second position, wherein themeans for laterally moving said lock elements includes an expander andmeans for effecting engagement of said lock elements with said expanderincluding a fluid pressure operated piston, said lock elements beingcarried by said piston, said one of said sections having a chamber inwhich said piston is disposed, and said sections having passage meansfor admitting uid to said chamber and discharging fluid from saidchamber including a passage leading into said chamber through said rod,and check valve means for closing said passage upon expansion of saidlock elements by said piston.

4. An adjustable tail pipe for operating a well tool upon engagement ofsaid tail pipe with the bottom of a well, comprising telescopic upperand lower sections, releasable means interconnecting said sectionstogether in a first relative position and releasable responsive to theapplication of a force tending to telescopically shift said sectionsfrom said first position, and means including coengageable lock elementson said sections for positively interconnecting said telescopic sectionsin a second relative position following telescopic shifting of saidsections, one of said telescopic sections including a connecting rodtelescopically extending into the other section, said means forinterconnecting said sections in said second position including asupport at the inner end of said rod, laterally movable lock elements onsaid support, axially opposing shoulders on said support and said othersection, and means for laterally moving said lock elements from aretracted position to a laterally shifted position between saidshoulders to hold said sections in said second position, wherein themeans for laterally moving said lock elements includes an expander andmeans for effecting engagement of said lock elements with said expanderincluding a uid pressure operated piston, said lock elements beingcarried by said piston, said one of said sections having a chamber inwhich said piston is disposed, and said sections having passage meansfor admitting fluid to said chamber and discharging fluid from saidchamber including a passage leading into said chamber through said rod,check valve means for closing said passage upon expansion of said lockelements by said piston, and an- 8 other chamber on the other side ofsaid piston from the first-mentioned chamber, said piston havingpassages communicating with said both of said chambers.

5. An adjustable tail pipe for operating a well tool upon engagement ofsaid tail pipe with the bottom of a well, comprising an upper tubularbody adapted for connection beneath a well tool, a lower tubular bodyincluding a rod telescopically extending into said upper body, means forreleasably interconnecting said bodies in relative positions with saidrod extended fully into said upper body, an upwardly facing shoulderadjacent the upper end of said rod, a downwardly facing shoulder in andadjacent the lower end of said upper body, lock means on said rod abovesaid upwardly facing shoulder, means for limiting telescopic extensionof said rod from said upper body to a relative position of said upperbody and lower body at which said downwardly facing shoulder is abovesaid lock means following release of said interconnecting means, andmeans for expanding said lock means for engagement with said downwardlyfacing shoulder and engagement with said upwardly facing shoulder tomaintain said rod in said extended position.

6. An adjustable tail pipe as defined in claim 5, wherein the means forexpanding said lock means includes a piston disposed about said rod,said lock means including expansible lock elements carried by saidpiston and engageable by said downwardly facing shoulder, said lowerbody having a passage leading therethrough and having a downwardlyseating check valve therein, said upper member having a top closureforming with said barrier piston a pressure chamber into which said rodextends.

7. An adjustable tail pipe as defined in claim 6 wherein said piston isprovided with restricted passages therethrough for dashpottingengagement of said downwardly facing shoulder Vwith said lock elements.

8. An adjustable tail pipe as defined in claim 6, wherein said piston isprovided with restricted passages therethrough for dashpottingengagement of said downwardly facing shoulder with said lock elements,said rod below said piston and said upper body forming a sectionalchamber into which said restricted passages extend, and said upper bodyhaving a port leading to the exterior thereof from said second chamber.

References Cited UNITED STATES PATENTS 2,182,888 l2/1939 Whitaker166-147 2,365,052 12/ 1944 Chamberlain 166-185 X 2,537,413 .1/1951Lawrence 166-212 X 2,575,105 11/ 1951 Hart et al. `166--237 2,808,11310/ 1957 Miller.

2,906,342 9/195'9 Russell et al 166-237 X 2,931,438 4/ 1960 Thompson166--243 X CHARLES E. oCoN-N'ELL, Primary Examiner.

IAN A. CALV-ERT, Assistant Examiner.

U.s. c1. xn. 16s-147

